1. Field of the Invention
The present invention relates in general to an air cleaner for cleaning the air fed to an internal combustion engine, and more particularly to an air cleaner of a type which uses a flat filter element.
2. Description of the Prior Art
Hitherto, various types of air cleaners have been proposed and put into practical use particularly in the field of internal combustion engines for motor vehicles.
One of the conventional air cleaners hitherto proposed is shown in FIG. 13 of the accompanying drawings. The air cleaner comprises a casing having air inlet and outlet tubes 3 and 5 secured thereto, and a flat paper filter element 2 set in the casing 1 to partition the interior of the casing 1 into a dust side chamber 4 to which the air inlet tube 3 is exposed and a clean side chamber 6 to which the air outlet tube 5 is exposed. In the illustrated conventional air cleaner, the filter element 2 is somewhat inclined with respect to the casing 1 for the purpose of increasing the filtration area of the filter element 2 and thus increasing the filtration capacity of the air cleaner. The air cleaners of this type are described in Japanese Utility Model First Provisional Publications Nos. 59-103856 and 60-77764.
However, due to inherency in construction, the air cleaners of this conventional type have the following drawbacks. That is, when increase in the filtration capacity is needed, a correspondingly larger filter element must be prepared for the air cleaner casing 1. However, this causes directly an increase in size of the casing 1. As is known, bulky construction of the air cleaner is disadvantageous in view of the jam-packed engine room of the latest motor vehicle. Furthermore, usage of a larger filter element tends to produce an undesirable vibration thereof in the casing 1 during running of the associated motor vehicle, which causes a generation of undesirable noise from the air cleaner.